If you want her to carry it and develop proficiency with it, LET HER CHOOSE HER OWN GUN!

Take her to a range that rents a wide variety of guns, introduce her to the owner or other knowledgeable staff member and then go get a long lunch by yourself while she stays at the range trying the guns that interest her.

Have her call you once she’s made her selection.

THEN you return to the range to see what she bought!